Dune holds up way better if you pretend it's just one book (the first one). It stands alone very well and IMO is completely worthy of its status in the classic sci-fi pantheon.
On the other hand, I finished TBP, but I disliked it enough that I didn't go back to the other two volumes. What makes them better than the first, in your opinion? (purely for my own curiosity re: whether I should go back and read them)
The first book is more character driven and the plot moves slowly, glacially compared to the next two. I don’t want to ruin the plot, but I‘d say they exceed Dune’s vastness without the long grinds.
The author described how he approached the series as wanting to write about the “the worst possible universe”.
I recommend you read books 2 and 3 in the REP series. TBP is comparatively really slow (IMO necessarily), but the series really picks up in 2 and 3 in a way that makes you appreciate the foundation that book 1 laid.
On the other hand, I finished TBP, but I disliked it enough that I didn't go back to the other two volumes. What makes them better than the first, in your opinion? (purely for my own curiosity re: whether I should go back and read them)